1. Technical Field
The present invention relates to a cryosurgical system, and in particular to a cryosurgical system that features a vibrating cryoprobe.
2. Description of Background Art
In cryosurgery, penetration of a cryoprobe into a dense tumor can be a primary challenge. Several approaches to meet this challenge are known.
For example, U.S. Patent Publication No. 20070149959 “Cryoprobe for low pressure systems” describes a cryoprobe with a pointed distal penetrating segment, which makes penetration into a tumor significantly easier. However, such cryoprobe has a significant drawback: it is too traumatic for any non-target tissue situated behind the target tumor, which is also likely to be damaged during treatment of the tumor.
Apart from cryotherapy, other patents describe the application of vibrations to other types of surgical instruments with concomitant easier penetration into living tissue.
U.S. Pat. No. 7,252,648 “Ultrasound puncture system” describes an ultrasound puncture system, which comprises a handpiece which accommodates an ultrasound vibrator, a puncturing probe for transmitting ultrasound waves to a biological wall which is to be punctured, an outer cover tube covering the probe and attached to the handpiece, and an ultrasound power source unit for driving the ultrasound vibrator, wherein the ultrasound power source unit comprises a termination unit for terminating the energy supply to the ultrasound vibrator, an impedance detector for detecting the puncture state of the probe, and a fluid supply unit for supplying a fluid to the distal end opening of the outer cover tube and probe, wherein the penetration of the probe through the biological wall is detected with the detection unit and the supply of energy to the ultrasound vibrator is terminated based on the detection output.
U.S. Pat. No. 6,908,472 “Apparatus and method for altering generator functions in an ultrasonic surgical system” teaches a system for implementing surgical procedures, which includes an ultrasonic surgical hand piece having an end-effector, a console having a digital signal processor (DSP) for controlling the hand piece, an electrical connection connecting the hand piece and the console, and a memory, such as an EEPROM (Electrically Erasable Programmable Read Only Memory), disposed in the electrical connection. The console sends a drive current to drive the hand piece which imparts ultrasonic longitudinal movement to the blade. However the blade only moves through application of ultrasound.
U.S. Pat. No. 6,765,333 “Power assistance device for an ultrasonic vibration dental handpiece” describes a power assistance device for an ultrasonic dental handpiece (5), which again relies upon ultrasound.
U.S. Pat. No. 6,702,761 “Vibration assisted needle device” describes a vibration assisted needle device for use in medical procedures, such as needle aspiration biopsies. Reciprocation of the needle, such as a biopsy needle, eases the advance of the needle through tissue, penetration of the site of interest and the collection of sample at a site of interest. The device comprises a housing defining a chamber, a needle support external to the chamber for supporting a needle and a mechanism in the chamber for causing reciprocal motion of the needle support. The needle support is preferably external to the housing. A syringe support may be connected to the housing for supporting a syringe. The reciprocal mechanism may comprise means for converting rotational motion into reciprocating motion, such as a bearing or a rotor with a circumferential, angled groove on its surface, coupled to the needle support. The bearing or the rotor may be driven by a rotational motor, preferably located outside of the housing, or by a hydraulically driven turbine within the housing. Alternatively, the reciprocal mechanism means may comprise a stationary solenoid and a movable solenoid for being coupled to the needle. Preferably, a second stationary solenoid is provided and the moving solenoid is between the two stationary solenoids. Energization of the stationary solenoid or solenoids by an alternating current, for example, and energization of the movable solenoid by a direct current, or vice a versa, attracts and repulses the movable solenoid, causing reciprocal of the needle. Methods and systems using the vibration assisted needle device are also disclosed. However, only the needle is provided for treatment, without any other type of treatment.
U.S. Pat. No. 6,497,714 “Ultrasonic trocar” describes a trocar having a needle unit. The needle unit has a paracentric section, which is substantially pyramidal. The paracentric section has two curved surfaces that diagonally oppose each other. The surfaces are formed by cutting the ridges of the section, which diagonally oppose each other. The remaining two ridges of the paracentric section make, respectively, sharp cutting edges for cutting living tissues. The cutting edges are substantially symmetrical to each other with respect to the axis of the needle unit. However, this device is only operative with a trocar for deep surgical (cutting) procedures.
U.S. Pat. No. 6,053,906 “Ultrasonic operation apparatus” teaches a control unit, which comprises a load state detector for detecting a load state of a load acting on a treatment section when the treatment section is put in contact with a living tissue, and a bar-graph display for indicating the load state in relation to ultrasonic oscillation on the basis of a detection result from the load state detector; again it only operates on the basis of ultrasound.
U.S. Pat. No. 5,728,130 “Ultrasonic trocar system” describes an ultrasonic trocar system, which includes a cannula having a guide bore, an obturator to be passed through the guide bore of the cannula so that the obturator can be removed, and a vibration generator for generating ultrasonic vibrations to be propagated to the obturator. The obturator is vibrated at an ultrasonic frequency to puncture a somatic layer. An intermediate member is interposed between the cannula and obturator. Again this device relies upon ultrasound.
Another challenge, which is related to the operation characteristics of cryosurgical probes, is achieving sufficiently large ice-ball in the freezing process and, therefore—achieving sufficiently large necrosis zone of the target tissue. However, there are currently no solutions available that provide both good penetration to dense tissue and also provide a sufficiently large ice-ball during the freezing process.